| Type | MGI:General | Description | at embryonic day 14 the flank epidermis is composed of several layers of flat cells and is approximately twice as thick as normal, while the dorsal and head skin remains thin at embryonic day 15 thickened epidermis extends to include the dorsal region and the hair nodules are delayed in appearance at embryonic day 16 the spinous layers are irregularly thickened and there are several layers of flattened cells above them while normal epidermis becomes wrinkled from embryonic day 17 onward, the epidermis of the homozygote remains smooth normal stratification of the epidermal layers is disturbed and on embyronic day 18 the basal layer has numerous lobes penetrating into the dermis, the hair follicles are irregularly spread between these lobes, the stratum spinosum is thickened with the superficial horny layers of the skin lacking or reduced, and the stratum granulosum is delayed in formation and varies in thickness |
